Health Information Library

What Is Soy?

You may have heard about soy foods in the news, including claims that soy prevents diseases such as cancer and heart disease. So what's the story on soy?

Soy, a versatile bean, is found in foods like soy milk, soy sauce, miso (soybean paste), tempeh (which is kind of like a soy cake), and tofu. Soy is also sometimes added to foods like breads, cereals, and meat products, and used as a meat substitute in vegetarian products such as soy burgers and soy hot dogs.

Foods that contain whole soy are a good source of protein for vegetarians and vegans because they provide all the amino acids — a type of nutrient — that people need to stay healthy. (People who eat meat get all their essential amino acids from animal products.)

What Are the Benefits?

Many Americans have added more soy to their diets because of increased availability and scientific studies that have shown that soy may offer health benefits, including lowering blood cholesterol and reducing the risk of certain cancers.

Past research suggested that soy protein could significantly lower levels of LDL cholesterol. But when the American Heart Association (AHA) reviewed the latest research, they concluded soy does not directly influence heart health.

The real health benefits of soy might lie in its nutritional content and the fact that people often use soy foods as a replacement for less-healthy foods. Soy foods are a great source of protein and contain other important nutrients, such as fiber, B vitamins, and omega-3 fatty acids. Foods containing soy protein are also a healthy alternative to meats and other animal products that contain cholesterol and saturated fat.

Soy in Your Diet

Soy milk, soy burgers, and soy snacks are available in many supermarkets and specialty stores. When selecting soy foods, be sure to check food labels to be sure that the food is a good source of soy protein and is low in saturated fat, cholesterol, and added sugar.

If you're interested in eating more soy, introduce it into your diet gradually. And remember that the key to good health is to eat a wide variety of nutritious foods without focusing too much on any one food.